US2096620A - Time switch - Google Patents

Description

Oct. 19, 1937. A, ROBERTSON 2,096,620

TIME SWITCH Filed Oct. 1, 1936 Inventoi": James A. Robertson,

Patented Oct. 19, 1937 UNITED STATES PATENT OFFICE TIME SWITCH Application October 1, 1936, Serial No. 103,546

8 Claims.

My invention relates to time switches and in particular to a combined time switch and clock wherein the switch may be set to close and open a circuit of a radio receiver or other device in accordance with a selected schedule during a twelve-hour period.

The object of my invention is to provide an improved timer of this type. particularly with respect to the timing accuracy, the reliability, and the positiveness of the switching operation. Other features of the invention will appear as the description proceeds.

In carrying my invention into effect, I provide, in combination with a clock, a rotary switchoperating member driven by a spring, which is gradually wound by the motor which drives the clock. The switch operating member is released by a double escapement mechanism at selected times. By this arrangement, suilicient force for positively and quickly operating the switch is made available without imposing sudden and erratic loads on the clock motor, and good timing accuracy of the switch operations is obtained.

The features of my invention which are believed to be novel and patentable will be pointed out in the claims appended hereto. For a better understanding of my invention, reference is made in the following description to the accompanying drawing in which Fig. 1 shows a face view of my improved timer, Fig. 2 an expanded perspective view of its operating mechanism and its circuit connections and Fig. 3a modification in the escapement mechanism thereof.

As shown in the face view of the timer, Fig. 1, there is provided an ordinary clock dial with hour, minute, and second hands III, II, and i2, respectively. Surrounding the time graduation circle is a circle of pins l3, which are slldable in an axial direction in a plate l5 through a limited distance. In the present illustration, there are forty-eight such pins evenly spaced and they are, therefore, spaced apart a distance corresponding to fifteen minutes travel of the hour hand of the clock. These pins are for the purpose of setting the program of switch operation. When the pins are pushed in to the limit of their travel, no switching operation occurs. If a pin is pulled out, as'

shown at It, Fig. 2, a switch-closing operation occurs when the hour hand reaches the time position of the pulled-out pin, the switch so closed remains in the closed position for fifteen minutes in the embodiment illustrated, and then opens if the next pin is not pulled out.

A person may by the use of this timer arrange any desired program of fifteen-mlnute-switching operations for a period of nearly twelve hours in advance of the position of the hour hand. For example, if, in Fig. 1, the pin opposite twelve oclock is pulled out, the timer will close a switch from twelve to twelve fifteen o'clock, If at the same time or prior to the time the hour hand reaches the next pin it is also pulled out, the switch will remain closed until twelve thirty. In the same way, pins opposite any of the other time positions may be pulled out and the switch will be closed for the fifteen-minute periods selected at the hour hand time selected. If a number of consecutive pins are pulled out, the switch will remain closed continuously during the time the hour hand is passing the positions of the pulledout pins. The mechanism may also be provided with means for automatically returning the pins to the in or idle positions shortly following the switching operations performed, if that is desirable. Such feature, if provided, assures that no switching operation will be repeated in a subsequent twelve-hour period unless the timer is subsequently set for a repeat operation. The mechanisms by means of which these functions are performed are illustrated in Fig. 2, which shows an exploded or expanded perspective view of the operating mechanism and a section of the front plate It which supports the slidable setting pins IS.

The clockwork with which the switch is combined is driven by any suitable form of timer motor, here shown as a self-starting synchronous motor I6, the field coil ll of which is connected to a source of regulated frequency alternating current II. The terminal shaft iii of the motor is assumed to rotate at one revolution per second and is geared to second hand shaft of the clock through similar gears 2| and 22. The minute hand ll of the clock is secured to a hollow shaft 23, which is driven from the shaft 20 through suitable speed-reducing gears 24, 25, 28, and 21. Gear 21 forms one part of a friction clutch in order that the minute and hour hands may be set. The other part 28 of the clutch is socured to shaft 23. The hour hand III of the clock is secured to another hollow shaft 29 driven from shaft 23 through suitable speed-reducing gears 30, 3t, 82, and 33. The difl'erent pointer shafts have the same axis of rotation and are driven at their correct time-keeping rate in a clockwise direction in the usual manner.

The switch, which is included in the timer, comprises a pair of spaced apart spring blades 34 mounted at one end in an insulating terminal block 35 for connecting the switch in any circuit which is to be controlled. In the illustration, the switch is connected to control the circuit of a radio-receiving set 26, which is energized from the same source it that supplies the clock motor. The movable ends of the resilient switch blades are separated by a rotary cam plate of insulating material having alternately spaced thick and thin cam lobes 38 and 38 about its periphery. When a thin lobe 39 is rotated into the position between the switch blades 34, the blades spring towards each other to join contacts l0 thereon which face each other and thus close the switch. When a thick lobe 33 is rotated into position between the switch blades, as shown, they are forced apart to separate the contacts I to open the switch. The thick and thin lobes are connected by suitably beveled surfaces so that, as a thick lobe is rotated into switch-opening position, no locking action of the rotary cam occurs. The energy for rotating the switch-operating cam is gradually stored in a spring 4| from the clock motor l6 and the spring is released as required to rotate the cam. The spring ll is contained in a hollow drum 2, which is a part of the insulating material forming the previously mentioned switch-operating cam. The outer surface of the spiral springl has a driving connection with the inner surface'of the drum, which connection is allowed to slip to prevent overwinding of the spring but not to the extent to prevent positive driving of t b drum as required in a switching operation. The inner end of the spring is connected to a winding shaft 43 on which gear 3| is secured and which is thus continuously driven when the clock is in operation. It is thus apparent that there will be ample energy available for positively and quickly rotating the switchoperating cam as required but that this energy is not taken from the clock motor directly but is gradually stored and hence there is no detrimental sudden load thrown on the clock motor that might interfere with its timing accuracy.

Secured in driving relation with the cam and drum 2 at either end, there are escapement wheels 44 and 45. Cooperating with escapement wheel 44 is a double-pawl escapement member 48, which is operated whenever one of the pins I3 is pulled out into operating position and the hour hand of the clock moves past such position. The operating mechanism for escapement 46 includes an arm 41 secured to and driven with the hour hand of the clock and which is approximately in line with the hour hand of the clock. On an axially extending car 48 of the outer end of arm 41 is pivoted at 49 a lever 5|! having an inwardly projecting forked part 5i straddling shaft 29 and an axially extending pin 52 on which is rotatively mounted a smooth surfaced wheel or roller 53, the peripheral surface of which is positioned to contact with inwardly extending parts 5 of pins l3 only when such pins are pulled out or set for a. switch operation and the roller 53 is rotated opposite such set pins with the hour hand of the clock. When this happens, the roller 53 is depressed towards the shaft 29 a slight distance by part 56 as the roller 53 slowly moves past such part and this depressing is effective over a period of fifteen minutes more or less. Since the roller 53 is free to turn on its pivot pin 52, there is no wiping action between the contacting surfaces but rather a rolling action and, hence, friction and wear are minimized, the contacting surfaces having a long life, and no serious load is imposed on the clock motor. When roller 53 is thus depressed, lever 50 turns about its'pivot point 49 a corresponding amount andits forked end 5| moves to the rear along the shaft against a washer 55 which comprises merely a pusher member between the forked part 5| and the forked end of a lever 56 pivoted at 51 and having an arm 58 engaging a slot 53 in escapement member 46 The escapement member 43 is pivoted at 60 and is urged to rotate in a counterclockwise direction about such pivot by a spring 6| to a point where its rear pawl 62 is in engaging position with a tooth on escape wheel 44. when roller 53 is depressed, the end of arm 53 which engages slot 59 of escapement pawl ll is raised and the pawl is rotated clockwise about its pivot to raise the rear pawl 32 from blocking position with the escape wheel II and lower the front pawl 43 into blocking position with a tooth on the front side of escape wheel ll. when roller 53 has moved past the part 54 of any pulled out pin, the next successive pin being pushed in, the roller is allowed to return outwardly and is caused to do so by spring 6| acting through the levers 55 and 50.

The arrangement for communicating motion between levers 50 and 56 along the central axis of the clock shafts is made necessary by reason of the fact that lever 50 with driving arm 41 rotates with the hour hand shaft 29 and may be in any one of ,several radial positions when a rocking action of escapement pawl 46 is called for. The movement of the lever system SIP-5| is suitably limited in opposite directions by stops which consist of gear wheel 33 and arm 41 which, in the actual device, will be closer to the forked end of the levers than appears to be the case in this exploded view.

The pins l3 are guided in slots cut in a pair of spaced plates l5 and 63, which surround the clock dial. The pins l3 have projecting shoulders, such as 54, to limit their endwise movements and keep them from being pulled out and lost or pushed too far into the casing. Their rear ends are preferably forked, as shown at 55, to give them a resilient fit in the slots in plate 63 so that they will not slide too easily and thus get out of place accidentally. It is seen that the front edges of projections 5| are beveled and this permits them to be pulled out manually when directly over the roller 53. When a pin is thus pulled out when over the roller 53, the roller is depressed and it is thus possible to manually operate the escapement 46 by pulling out or pushing in that pin which happens to be over the roller 53. The roller 53 is of sufilcient diameter with respect to the spacing of the pins [3 that. when two adjacent pins are pulled out, the roller 53 will remain in the depressed position while passing both such pins. The eficctive time during which the roller is depressed is then approximately thirty minutes instead of fifteen minutes.

The arm 41 may be provided with a trailing cam part 56, which contacts the front edges of shoulders 54' of any pins which are pulled out as the cam 66 moves past and returns the pins which have thus been pulled out to the "in position. This nonrepeat feature may be omitted. if desired, by simply leaving off or bending back the cam part 56.

Referring now to the second escapement wheel 5 provided on the switch drum 42, it is seen that it has double the number of teeth of escapement wheel 44 but that its escapement pawl 61 has only one pawl tooth. The pawl 61 is pivoted at 58 and is urged towards the locking position shown by a spring 69. This pawl is periodically removed from looking position with respect to wheel 45 by a cam wheel I0 having four equally-spaced cams, each of which rock pawl lever El between locking and unlocking positions. Cam ll) is driven in a counterclockwise direction by the timing motor through gears 3|, 1|,and12.

Rod 13 is provided .with a thumb nut N on one end and a gear- 15 on the opposite end for setting the hands of the clock when desired.

aobaeao Normally, gear II is, demeshed from the gear train but, by pulling back on the thumb nut ll. gear I! may be meshed with one of the gears ll of the train and then turned to set thehands of the clock and likewise cam II.

In the embodiment represented where the setting pins it are spaced tor selecting switch operations at fifteen minute intervals and where the switch-operating cam has four thick and four thin lobes 3B and It, there should be four teeth in escape wheel 44 which cooperates with the double-pawl escapement lever 46 and there should ,be eight teeth in the escape wheel 45 which cooperates with the single-pawl escapement lever 61. Shaft 13 should be rotated at least one revolution in two hours to keep the spring ll wound under the maximum possible number of switch operations, 1. e., an operation every fifteen minutes which will require a oneeighth rotation of drum 2 every fifteen minutes. Where four spaced cams are provided in wheel l0, it should rotate at one revolution per hour, which represents a release of escapement 45 every fifteen minutes. It is assumed then that shaft 43 is rotated one revolution in two hours in a counterclockwise directi n, which winds the spring 4| as required; a so that gear wheel I! and the cam wheel Ill driven thereby rotate at one revolution per hour when the clock is in normal time-keeping operation.

It will be evident that this timer is operable without escape wheel 45, pawl lever 61, cam iii, and gear 12. However, these or equivalent parts are desirable where high accuracy of timing of the switch operation is called for and are to be included in the refined embodiment of my invention. It will be desirable to first explain the operation of the timer on the assumption that the parts last mentioned are omitted, both from the viewpoint that said parts may be omitted and also to present a clearer understanding of the operation of the difl'erent parts.

Assume then that we remove lever 61 so as to make the escapement it ineffective such that the only means for preventing rotation of the drum .2 is the escape wheel 44 and its escapement mechanism. Assume that the clock is in operation and that no pulled out pins are touching roller 53 so that spring 6i holds escapement pawl 52 in looking position on the back side of wheel I4 and the levers 56 and 50 are in the corresponding positions shown. The switch at lil is open because a thick lobe 38 is inserted between the switch blades 34. Let us assume that the time indication of the clock is ten thirty and that we pull out a pin it opposite the ten fortyfive position of the hour hand so as to close the switch for a fifteen minute period beginning at ten forty-five. In a short time, roller 53 will move against projection 54 of pin l4 and the roller will start to be depressed. The forked end ii of lever presses washer 55 against the forked end of lever it, rod It starts to rotate escapement pawl 62 out of locking position and front escapement pawl It into locking position until finally, at about ten forty-five, escapement wheel 44 is released and is quickly rotated by spring ll one-eighth revolution where it is stopped by tooth 18 of wheel 44 coming in contact with the dotted line position of front pawl 46. In the meantime, a thin lobe 38 has exchanged places with a thick lobe between the switch blades 34 and these blades have closed the contacts at 40 connecting the radio receiver 26 in circuit. At about eleven o'clock, roller I3 will have passed by projection I4 and will have returned to the position shown, withdrawing pawl a from looking position with tooth It and returning pawl 62 to locking position. atwhich time drum I! will make another one-eighth revolution, tore.- ing a thick lobe 38 between switch blades I4 and opening the switch at ll. Subsequently, cam ll comes opposite projection ll of tooth i4 and. as the hour hand advances, tooth II is returned to the "in" position by cam 88.

Any desired fifteen-minute interval switching program may be arranged over a period of about eleven hours in advance or the time indicated by the clock by properly positioning the correspond'ng pins, pulling those pins out opposite the futuretime position of the hour hand when the switch is to be closed. and leaving those pins in opposite the time indications where the switch is to be open. Owing primarily to the fact that the motion of the hour hand is slow moving, it has been found impossible to obtain very good timing accuracy of the switching operations at the beginning and end of the fifteen-minute periods when using the single escapement 46. It has been found that, with the best practicable control of manufacturing tolerances, the timer with the single escapement could only with chiliculty be adjusted to operate the switch within a range of about three minutes. For example, with the pin opposite ten forty-five pulled out, the switch might close any time between ten fortytwo and ten forty-five and open anywhere between eleven and eleven three.

The addition of the second escapement decreases this range of error from about three minutes to not over one-half minute when a cam such as is shown at 10 is used, and this improvement is due primarily to the fact that the 8863138'. ment'mechanism 45, 61, It operates much faster so that dimensional variations in the manufactured parts of the same order as before produce considerably less error.

The adjustment and operation will now be described on the assumption that both escapements are present as shown in the drawing. Escapement wheel 45 is so rotatively adjusted with respect to escapement wheel I and cam it is so rotatively adjusted with respect to the clock hands that escapement M is used to stop rotation of the drum 2 and escapement 5 is used to release the drum. It is to be noted that, while pawl 61 moves to releasing position every fifteen minutes regardless of the position of setting pins it, no switching operation occurs unless shortly' prior to a releasing movement of pawl 61, pawl 46 or 62 has been moved to a releasing position due to the fact that a pin I3 is in a pulled out position and is causing inward or outward movement of roller 53. When a switching operation occurs, the escapement 44 and its controlling mechanism selects the fifteen minute period of its occurrence and escapement l5 and its controlling mechanism then determines more accurately the beginning and ending of such iiiteen-mlnute period,

Assuming that the pin opposite one o'clock hour hand time is pulled out, the sequence of operation is substantially as follows:

Between twelve fifty-three and twelve ili'tyseven. back escapement pawl 62 releases wheel 44. At this time, escapement pawl 61 is in locking position in a notch oi escapement wheel 45 and nothing else happens except that the drum 42 may rotate very slightly to take up any slack that there may be between the tooth of pawl 61 and the edge ofthe slot in wheel I! in which it is located. At approximately one o'clock, escapement I is released and drum 2 rotates oneelghth revolution to close switch ll. The rotation 5 of the drum isstopped at this point by the front pawl I of escapement wheel ll. At approximately onE'seven, escapement pawl 81 moves into the hxtmot'ch of escapement wheel 45. Between one'nihe and one twelve, the front pawl ll of escapement wheel 44 releases but nothing else happeds except possibly a slight advance of drum if'to take up any slack that may exist in the notch of wheel 45 in which its locking pawl 61 is now located. At approximately one fifteen, escapement pawl 61 releases and drum 42 rotates oneeighth revolution to open the switch, the drum being stopped by the back pawl 62 of escapement,

wheel ll. At approximately one twenty-two, escapement pawl 81 again moves into checking position in the next notch of wheel 4!.

If in addition to the pin l3 opposite the one oclock position, the pin opposite the one fifteen hour hand time had also been pulled out, the above described sequence of operation would have been modified as follows:

The events unto-and including time one seven would be the same as before. Front pawl lli is not released between one nine and one twelve because its operating lever mechanism is held in the existing condition by the projection 84 of the pulled-out pin l3 opposite the one fifteen o'clock hour hand time. Consequently, at one fifteen, when pawl Il moves to released position, the drum remains in the switch-closing position, it being held by front pawl ll. At approximately one twenty-two, escapment pawl 61 moves into locking position and returns to the same notch of wheel I! from which it was last removed. Between.one twenty-four and one twenty-seven, front pawl I6 is released and at approximately one thirty pawl 81 releases wheel 45 and the drum rotates one-eighth revolution to open the switch, the drum being stopped by back pawl B2 of escapement wheel 44. At approximately one thirtyseven, pawl 81 again moves into its locking position.

It is seen that this device retains the convenient and easily understood setting feature which is inherent in providing the setting pins l3 coordinated with the time indications about the clock dial. However, it avoids the inherent inaccuracy oi the slow-motion control mechanism, which is necessarily used in obtaining this convenience by providing a second and faster moving control 55 mechanism for more exactly determining the time of switch operation.

The speed of operation of the cam wheel 1a and its escapement lever 51, as arranged in Fig. 2, is ordinarily suflicient but it will be evident that a 00 still faster movement and hence more accurate timing of switch operation can be had, if desired. For example, in Fig. 3, I have shown a cam 8|! having one rise and one drop in its surface for operating the escapement lever 8| for the escape 55 wheel 45. In this example, the cam 80 will be geared to the clock train to make one revolution in fifteen minutes. The releasing of escape wheel I! is accomplished very quickly by the spring 82 when this is permitted as lever 81 rides over the 70 drop in the cam 80. It will be noted that the drop in cam wheel 80 is not exactly radial but slopes slightly in a direction and to the extent necessary to let the cam following pin of lever 8| down over the drop without making objectionable 7 noise.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention together with the apparatus which I now consider to represent the best em bodiment thereof but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim is new and desire to secure by Letters Patent of the United States:

1. In combination, a clock and time switch, the clock having the usual dial and clock hands, a plurality of switch operation con'trol setting pins about the periphery of the clock dial coordinated with the time graduations of said dial, said pins being movable to operative and inoperative positions, a timing motor for operating said clock, a switch in said clock, a rotary switch-operating member having a plurality of switch-closing and switch-opening cams alternately spaced about its periphery, a spring wound by said motor for rotating said member, an escapement mechanism for controlling the rotation of said member arranged when operated to release said member and permit rotation thereof a distance corresponding to the spacing of the cams on its periphery, and a lever mechanism for operating said escapement mechanism including a part which is rotated with the hour hand of said clock, said part having a roller thereon, each of said pins having a part which is moved into the path of rotation of said roller when such pins are moved to operative position, whereby, when said roller is driven past an operatively positioned pin, said lever mechanism is moved in one direction and the escapement mechanism operated, and a spring for moving said lever mechanism in the opposite direction to again operate said escapement mechanism.

2. Arcombined time switch and clock having the usual clock dial and time-indicating hands, a plurality of switch operation control setting pins about the periphery of said-dial coordinated with -=the time graduations thereof, said pins being movable between operative and inoperative positions, a switch in said clock, a timing motor for driving said clock, a rotary switch-operating member having switch-closing and switch-opening cams alternately spaced about its periphery for closing and opening said switch, a spring wound by said motor for rotating said cam member, an escapement mechanism including a lever system which, when operated, permits the rotation of said member the distance corresponding to the spacing of the cams on its periphery, said lever system having a part driven with the hour hand of the clock and engageable with an operatively-positioned pin when driven past such pin for operating said lever system in one direction at approximately the hour-hand time indicated by the position of such pin, a spring for moving said lever system in the opposite direction, and other means operated by said clock for periodically releasing and locking said rotary switch-operating member, said means being timed to release said member as the hour hand of the clock passes each pin and serving to more exactly time the instant of any switch operation that has been selected to occur at approximately such times by operatively positioned pins.

3. In a. combined clock and time switch, clockwork includlng an hour hand, a. clock dial with which said hand cooperates, a pair of perforated, spaced plates concentric with said dial and extending beyond the periphery of said dial, a plurality of pins supported in the perforations of said spaced plates, evenly spaced about said dial, and coordinated with the time graduations of said dial, said pins being slidable endwise in said plates between operative and inoperative posi tions, each pin having shoulders which strike the plates and limit the endwise movement of said pins, said pins having a split portion which extends through one of the plates to give the pin a resilient fit in the perforation 01 such plate, said pins having inwardly extending switch-controlling projections, and a lever arm driven with the hour hand of the clock adapted to contact with the inwardly projecting parts of said pins as said lever arm is driven past the same only when said pins are slid endwise to operative position to produce a switch-controlling movement of said lever, said pin projections having a beveled surface, whereby a pin opposite said lever may be manually slid between its endwise positions to manually produce switch-controlling movements of said lever.

4. In a combined clock and time switch, a clock having a dial, an hour hand of said clock cooperating with said dial, a pair of spaced, perforated plates concentric with said dial and extending beyond the periphery of said dial, a plurality of switch-controlling pins supported in the perforations of said plates, evenly spaced about the periphery of said dial, and coordinated with the time graduations thereon, said pins being slidable in said plates between operative and inoperative positions, a switch-controlling lever arm driven with said hour hand past said pins, said pins having inwardly projecting extensions which, when a pin is moved to operative position, its projection is moved into the path of rotation of said lever and, as the lever is driven past an operatlvely-positioned pin, the lever is moved inwardly to perform a switch-controlling operation, and a trailing cam part on said lever for moving operativelypositioned pins to the inoperative position shortly after the lever has been driven past such pins.

5. In a combined time switch and clock, a clock dial, an hour hand cooperating with said dial, a switch-controlling lever driven with said hour hand, a plurality of switch-controlling setting pins supported about said dial and coordinated with time graduations on said dial, said pins being movable between operative and inoperative positions, a lever arm rotated with the hour hand, and a roller on the outer end of said lever, said pins having inwardly extending projections which, only when the pins are in operative position, extend into the path of rotation of the surface of said roller such that, as the roller is driven past such pin, it rolls on and over such projection and produces switch-controlling movements of said lever, the contacting surfaces of such pro Jections and roller being such that a pin opposite the roller may be manually moved between its two positions to produce switch-controlling movements said lever.

6. A combined time switch and clock, a timing motor for driving said clock, a switch comprising a. pair of resilient contact blades supported at one end and having normally closed cooperating contacts at their other ends, a rotary drum of insulating material having alternately spaced thick and thin cam lobes about its'periphery adapted, as the drum is rotated, to move between the resilient contact blades, the dimensions of the lobes being such that, when a thick lobe is inserted between said blades their contacts are separated and, when a thin lobe is inserted between said blades their contacts are closed, a spring in said drum for rotating the drum, said spring being wound by said timing motor, the driving connection between said spring and drum permitting slipping only when the spring is wound up, which prevents overwinding of said spring, escapement means for said drum for permitting intermittent rotation thereof, each such movement corresponding to the spacing o! the cam lobes thereon between switch-operating positions, and switchcontrolling setting means for determining the times or operation of said escapement and the rotary movements of said drum.

7. A combined time switch and clock having the usual clock dial, hour hand, and driving timing motor, a switch in said clock, a rotary drum for controlling the operation of said switch, a spring wound by said motor for rotating said drum, an escapement for said drum for controlling the extent of rotation of said drum, a lever system for operating said escapement, a plurality of pins evenly spaced about the clock dial, said pins being coordinated with the time graduations and movable between operative and inoperative positions to select the program of switch operation, the lever system having a part driven with the hour hand of the clock past the pins and having a roller which is adapted to contact with any operatively-positioned pin as it is driven therepast to move said lever system in one direction to operate said escapement and permit the drum to rotate from a switch-opening to a switch-closing position, and a spring for returning said lever system in the opposite direction to again operate said escapement to permit the drum to rotate from a switch-closing position to a switch-opening position when said roller has moved past an operatively-positioned pin; the contacting surface oi said roller being sufiicient to contact with two consecutive pins which are moved to operative positions so as to prevent the return of said lever system and the opening of said switch until said roller has moved past all of the consecutive pins which are in operative position.

8. A combined time switch and clock comprising, clockwork with the usual dial, hour hand, and timing motor, a switch, a rotary member for operating said switch having switch-closing and switch-opening positions, a spring wound by said motor for rotating said rotary member, setting pins uniformly spaced about the clock dial at definite time intervals apart as measured by said hour hand, said pins being manually movable between operative and inoperative positions, a lever system having a part driven with the hour hand past said pins and adapted to be contacted by any pin which is in operative position when opposite thereto, an escapement mechanism for said rotary member operated by said lever system in response to such contact, and a second and faster moving escapement for said rotary switch member operated in response to the operation of said clock once for each such time interval regardless of the positioning of said pins, said escapements being timed to operate such that, when a switch operation is to occur as determined by the time position of an operatively positioned pin, the first mentioned escapement releases said rotary switch member while it is held from rotation by the second mentioned escapement, the second mentioned escapement then operates to release said rotary switch member and it rotates by an amount to close the switch it open or to open the switch if closed and said rotary switch member is then stopped by the first mentioned escapement.

JAMES A. ROBERTSON.

mit M 7 CERTIFICATE OF CQRRECTIQN. Pst entwflo. 2,096,620. October 19, 1957.

JAMES A. ROBERTSON.

It i s tjfereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, second colizmn, line 51, for the word "second" read minute; and that the said Letters Patent should be read with this correction therein that the same may conform to the: record of the case in the Patent Office.

Signed and sealed this 25th dsyof January, A. n. 1953.

Henry Van Arsdale, Acting Commissioner of Patents.

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